Reamer cutting machine



Oct. 18, 1932. ALBERTSQN 1,882,691

REAMER CUTTING MACHINE Filed Dec. 16, 1929 6 Sheets-Sheet l OEL 18,1932.

F. o. ALBERTSON 1,882,691 REAIER CUTTING IEACHINE Filud Dec. 16, 1929 6Sheets-Sheet 2 1932- F. o. ALBERTSON 1,832,691

REAMER CUTTING MACHINE Filed Dec. 16. 1929 6 Sheets-Sheet 5 Oct. 18,1932. ALBERTSQN 1,882,691

REAMER CUTTING MACHINE Filed Dec, 16, 1929 6 Sheets-Sheet 4 1 4 cj/y 0Java Oct. 18, 1932. F. o. ALBER-TSON 1,832,691

REAMER CUTTING MACHINE Filed Dec. 16, 1929 s Sheets-Sheet 5 Oct. 18,1932. ALBERTS-ON 1,882,691

REAMER CUTTING MACHINE Filed Dec. 16, 1929 6 Sheets-Sheet 6 wa /722i.fia/zs 6%6/730/7 2% z wim.

Patented Oct. 18, 1932 UNITED, ATENT?- OFF-ICE? FRANS o. 'ALBE-RTSON, oraogmm; mwa ssrG'Non Tovannnntrsofi e, COEPANY} 1 INCL, or srouxcrrY,IOWA, A CORPORATION or IOWA REAMER CUTTING MACHINE Application filedDecen1berr16, 1929. Serial Yo. 414,892;-

i The present invention relates to reamer cutting machines, andis-particularly con cerned withthe provision of an improved reamercutting machine which is peculiarly adapted for the manufactureofimproved valve seat finishing reamers having new and desirable operatingcharacteristics. I v

The reamer adapted to be manufactured by the presentmachine, and themethods of making reamers and finishing valve seats, are the subject ofanotherapplication filed byl Frans O. Albertson on November 18, 1929,Serial No. 407,877, for valve seat finishing tools and methods of makingthe same and while some of the desirable operating characteristics in avalve reamer might be attained by the use of other machines for makingreamers, the present machine is an example of the preferred embodimentfor construct ing reamers of the type shownin my prior application. I II In the finishing or r eseating of the valves of internal combustionengines, the r'eamers or other tools of the prior art, have not beencapable of forming a perfectly finished valve seat, and ithas alwaysbeennecessary to use a lag'iping or grinding operation in orderfto attainthe degree of vperfection which is desirable for modern internalcombustion engines. This grinding or lapping operation is usuallyperformed with the-valve in place, by putting a small amount of grindingcompound on the seat or valve and by oscillating the valve upon its axiswith the valve engaging the seat, and the grinding of the valve on theseat is relied upon to secure a perfect fit between the valve and theseat in thedevices of the prior art.

The reason for such lapping or grinding operation was that it waspractically impossible for the prior reamers to finisha valve seat witha uniformly perfect seating surface and a close examination and test ofthe valve seats made by the tools of the prior art shows that there arenumerous waves in the surface of the valve seat, consisting of minutehills and valleys, generally extending radially with respect to the axisof the valve and seat. i

One of the most important factorscontribf uting to this lack ofperfection of the valve seats made by the prior tools was the tendencythe arthave sought for many years to avoid the chattering of the reamer,generally by varying the, number of teeth used and by using an oddnumber of teeth.

. None of the devices of the prior art have been able entirely toeliminate the chattering and-resultant high and lowspots producedinthevalve seat, and consequently the finish-,

ing ofvalve seats with the tools of the prior art always consisted ofatleast a two-step,

method, the last step being the lapping in r of the valve with the valvegrinding com-v and a machine for oscillating the pound valve; 1

Oneof the objects'of the present invention is theprovision of animproved reamer cuttingmachine which is adapted to produce animproved-valve reamer capable of finishin valve seats by an improvedone-stepimethof, by means of which the customary grinding orlappingoperation may be eliminated r Another object of the, invention is thepro vision of an improved machine: capable of producing improved valveseat reamers or valve reconstruction tools, which have theinherentcapability of producing a substantially perfect valve seatsurface. s I

Another object is the. provision of an improved machine adapted tomanufacture reamers having improved operating characteristics from whichthe undesirable factor of chattering orv uneven cutting, present in thereamers of the prior art, have been eliminated. I

Anotherobject, is the provision of animproved machine which is capableof the economical and expeditious cutting of teeth for valve seatreamers or the like, having a plurality ofvteeth which are located atdifi'erent spacing from each'other, each at a slightly different anglewith respect to the angularity of the surface relative to the axis ofthe reamer, and each having a different angularity with respect to theelementsof the" conical valve seat surface;

Other obj ects-and advantages of the inven- Fig. 2 is afrontelevationalview of the same machine, with certain parts in section onthe plane of the 'line2+2 of Fig.1-to illustrate the mechanism 7 v Fig.3 is a pl n view of the guide for the table,- partially broken away toshow the mechanism for feeding the table;

Fig. dis a sectional view onthe plane of the line i1 of Fig. 6 throughthe eccentric spindle, for supporting the reamer blank; Fig-5 is a-planview of the dividing head; Fig. 6 is a sectional view taken on the planeof the line 6 6 offFig. 5, looking in the direction of the arrows;

Fig. 7 is an enlarged bottom plan view of areamer made by the presentmachine Fig. 8 is a sectional view taken on the plane of line 88 of Fig.7; r

Fig. Sis a diagrammatic, elevational view showing the relation betweenthe milling cutter and reamer blank during the cutting operation nism.:46

Fig. 10 is a plan view in partial section, of

the automatic table elevating mechanism; and

I Fig. 11 is a vertical sectional view taken on the plane of the line11-11 of Fig. 2, through the table supporting and adjusting mecha- As anunderstanding of the results sought to be accomplished, and thecharacteristics of the reamer manufactured by the present 'machine, isessential to an understanding of the machine, I shall first-brieflydescribe the structure and characteristics of the improved reamers madeby the present machine. These features are-more fully described in myabove mentioned prior application.

. Since the improved features and characteristics of the teeth aredifiicult to distinguish with the naked eye, the views of Figs. 7 and 8have been drawn on a scale three times the actual size of one of thecommercial reamers. The 'reamers are preferably constructed ofsubstantially cylindrical bodies 10 of the best tool steel and providedwith a substantially flat upper surface 11 for engagement with feedingdevices and with a slightly tapered bore 12 having its largest endlocated at the top 11 of the reamer, so that thereamer 10 may be securedupon a tool holder by the frictional fit of a complementary taperedportion in the tapered bore 12. V

The body 10 of the reamer is cut away at regular intervals around thelower and outer edge of the reamer, with a plurality of cuts, preferablyof triangular section, forming substantially flat walls 15 and 16 oneach side of the cut, forming the teeth 17 provided with cutting edges18. The cuts which form thewalls 15 and 16 are made diagonally I withrespect to a certain axis on the reamer, so

that the teeth 17 thus formed, extend substantiallyalong/ the angle ofthe reamer desired.

Thus, for a 45 reamer, the general direction of the feed of the cuttingtool is at 15 to the axis of rotation of the reamer which is being cut,but reamers may be made of any angularity, the ordinary commercial sizesof reamers being 15, 30, 45, 50, 60 and 75, and it will be understoodthat any desirable size of reamer may be constructed.

It should be understood that the exact shape of the cuts produced by thecutting tool depend upon the type of tool employed,'and the provision ofsubstantially flat sides on the teeth 17 is incidental to the cutting ofreamers with milling tools. I

One of the most important features of the present. reamer is theexact'directionin which cutting edges 18 extend with respect to the trueaxis of the reamer. The true axis is indicated by the numeral 19 and aneccentric axis upon the horizontal base line 20 is indicated by thenumeral 21.

It. has already been pointed out that the cutting edges of the reamersof the prior art produce minute irregularities such as hills and dales,extending radially of the surface of the valve seat, and it will beevident that the radial teeth of the reamers of the prior artwould'naturally fall into such valleys or dales between successive highpoints, thereby accentuating the undesirable result when it has oncebegun. The cutting edges of the reamers constructed according tothepresent invention, do not all extend radially at the same angle to theaxis of the reamer as in the devices of the prior art, but the variousteeth, or certain of them,'extend at substantially different angles toeach other and to the axis of the reamer.

The effect of this change in the direction of the cutting edges can bestbe understood by comparing the action of two radial cutting edges suchas are provided in the prior reamers, with two of the cutting edges ofthe present tools.

Assuming that one of the prior reamers had radial teeth and the firsttooth chattered slightly and produced some radially extending valleysand hills on the seat, the next radial tooth would be axactly in linewith the direction of these valleys and the undesirable chatteringeffect would be accentuated with furtherv undesirable results. Assumingthat thepresent valve tool was employed upon a seat which had such aradially extending irregularity, if one of theteeth happened to fit thisirregularity in alignment, the next the cutting operation. Thus, each ofthe cutting edges of the present reamer is preferably disposed at aslightly different angle,,butthe amount of divergence between a radialline and the cutting edges is so minute that it cannot bedistinguishedby the naked eye, alone.

In the reamer manufactured by the present machine, which represents aform most conveniently and economically manufactured, the cutting edge22 extends radially with respect to the true axis 19 of the reamer, butat. substantially 45 to said axis in a 45 reamer. Since the sameprinciples may be applied to reamers 'of any angle, it is only necessaryto,

describe the 4C5reamer, and theterm radially is used in the genome senseto include allof the lines inany radial plane, that is, a

plane which includestheaxis of the reamer. All of the other cuttingedges 23 to 35, inclu-' sive, extend along lines drawn to the point 21which is spaced slightly from the true center 19. 1 7 It will thus beobserved that all of the cutting edges extend substantially along lineswhich are radial with respect to the eccentric point or axis 21, andconsequently theangle between the cutting edges and a true, radial orplane, increases by steps from the edge 23 to the edge 29, and decreasesby steps from the edge 30 to the edge 36, the divergence between thecutting edge 22 and the radial line being theoretically equal to zero. a

Each of the teeth 17 is provided with a slightly flat or concavelycurved surface 37, which is formed bythe sharpening operation, and thejuncture of the surfaces 27 and 16on the various teeth, formsthe cuttingedges 22 to 36, inclusive. The particular form of teeth illustrated anddescribed, isthe result of the method of manufacture which will now bedescribed in detail. I

The exact location and direction of the teeth is difiicult to determineon account of i the minute measurements required and the complexity ofthe geometrical problems involved in specifyingthe exact di'rection,'butthe foregoing description has been provided in order to give oneaccepted theory of the operation of the present tool informing a aperfectly finished valve seat.

The angularity of the teeth varies, not only with respect to radiallines drawn from the 7 axis of the rea'mer, but certain'of the teethation, and anothertheory of operation'of'the present cuttingedges isthatthe reameri'sl providedwith one edge or tooth extending, truly at anangle of 45, whereasthe other teeth not only diverge laterally fromtheradial lines, but also diverge upward or downward fromithe true 45,tending to cut deeper at one end and shallower at'the other end, but thecomposite result of the entire setof teeth is known to be a practicallyperfect 45 valve seat."

Referring to Figs. 1 and 2, the reamer cutting machine selected toillustrate the invention, preferably includes 'azsupporting base whichisprovided with an upwardly extending column 51 having a cutter shaft 11rotatabl-y mounted'therein and provided with: a plurality of-pulleys52of differentsizes. The head ofthe column 51 preferably supports aforwardly extending bar 53 having a depending bearing member 54: for thecutter shaft' ll, and the shaft 41 is adapted-to sup port any one of' aplurality of differentmill ing cutters 40. c Referring to Fig.9, thepreferred milling cutter is provided with a plurality ofcuttin g edges55 and 56 which may extend in such manner that the milling cutter 40 isadapted to make a substantially triangular cut forming the teeth 17 inthe reainer 10, the teeth having relatively flat side walls 15 and 16.

,The column 51 of the machineis preferably provided with a,vertically'extending guide 57"of substantiallytrapezoidalcrosssect-ion, as shown'in Fig. 3, having inclined side walls 58 so thatthe guide 57 tapers in I width from its outer corners, inward to th bodyof the column 51.

The machine is also provided with a supporting member 59, usually termeda knee, which is adapted to provide a support for a plurality of slidingcarriages 60, 61, a dividing head 62 and other mechanism necessary I forthe support of the reamer body 10, from which the finished reamer ismade.

v The knee 59 is therefore provided with laterally projecting guidemembers 63 adapted to embrace the tapered guide member 57 on column 51,and slidably support the knee 59 on the column 51. "In order to providea manually adjustable and also automatically ad justable support forthe'sliding knee 59, the

knee ispreferably formed with a bearing 64 for rotatably receiving avertical screw shaft 65, and the lower end of screw shaft 65 isrotatably supported by a slider 66. The slider 66 is provided with athreaded bore 6'7 for receiving the lower threaded portion 68 of thescrew shaft 65, and the knee59 is provided with an aperture 69 forreceiving the slider 66, andwith a collar 70 having a bore 71 forreceiving the cylindrical portion 72 of "the slider 66.

the knee 59 and provided with a crank 87.

receiving a key 7 5 adapted to prevent rota tion of the collar 70, andthe downwardly in clined body 7 6 of collar 70 is fixedly secured totheknee 59 or held in position by the 79 and a pair of registering bores80 for receiv'ing a stub shaft 81 which rotatably supports a roller 82.f

The upper end of shaft 65 is provided with a'bevel gear 83 adapted tomesh with a bevel gear 84: carried by a horizontally extending shaft 85,rotatably mounted in bearings 86 in The base 50 of the milling machineis: preferably provided with a forward extension 88 adapted to provide asupport for a platform 89 which carries a vertically extending shaft 90for rotatablyrsupporting an elevation plate 91.' The elevation plate 91may consist of a circular member provided with a plurality of teeth '92having substantially radial shouldersl93, on one side, and inclinedcamming surfaces 94 on the other side, and the plate'91 is provided withan annular carnming surface 95, the-elevation of which is varied to varythe elevation of the knee 59,

and all of the associated mechanismssupported thereby. e n

In manufacturing reamers ofthe type de- Y scribed, it is preferable thatthe depth of cut be changed with respect to each successive tooth,thereby varying not-"only the space between the teeth, but the relative.angularitye of the respective teeth, and in order to accomplish thisresult, the plate 91 is provided with the camming surface 95 which hasa' different elevation for each successive tooth to be cut. Thus, whereit is desired tomake a fifteen tooth reamer, the machine is providedwltha plate 91 havmg fteen surfaces 96 of different elevation, forming anannular camm-ing surface 95.

Although the annular camm'ing surface 95 is shown with radial lines97-to indicate the divisions between the successive camming surfaces 96,it should be understood that the transition in elevation betweensuccessive surfaces 96 may be gradual, so that the rotation of the plate91 is adapted tocam upward the roller 82, knee 59 and the carriagessupported thereby.

It should also be understood that'the pres ent construction is notlimited to the type of reamer in which each and" every one ofthe teethdiffers in depth fronreach and every other tooth, but that certain ofthe cuts which are at some distance from other cuts, be substantiallysimilar in depth if desired, and

of a cross-section complementary to the guide a 98, so that the carriage101 is adapted to be slidably supported on the" knee 59. The carriage isprovided with a depending lug 101 having a threaded bore 103 forreceiving the threaded end 104 of a shaft 105, which is rotatably, butnon-reciprocably, supported in the knee 59,'and provided with anon-circular end 106. The carriage 60' may thus be slid forward orbackward by the application of a crank or tool to the squared end 106 ofshaft 105, and it will be evident that rotation of the shaft 105 willcause the table 60 to advance or recede.

The table 60 is also providedwith a groove 10'. adapted to receive aguide member 108 of similar form to those already described, carried bythe carriage or table 61, and the guide member 108 is preferably locatedat right angles to the guide 98 so that the table 61 may be movedtransversely to the axis of the cutter shaft 41.

In order to provide means for moving the table 61 and feeding the reamerinto the'cutter 40, the carriage 60 is preferably formed with adiagonally extending bearing 109, which rotatably, but nonereciprocably,supports a shaft 110, and the shaft 110 is provided with radiallyextending handles 111 and with a screw thread 112 adapted to engage arack 118 carried by the table 61. A rotation of the shaft 110' by meansof the handles 111, causes the table-61 to traverse the field of thecutter 40, and the reamer may thus be fed against the cutter 40 or with;drawn as desired, by actuating the handles 111. r The table 61 ispreferably provided with a plurality of transversely extending slots 111 of substantially T-shaped cross-section, for slidably receiving theheads of a plurality of bolts 115 which securethe base 116 of thedividing head 62 to the table 61, and the dividing head 62 may thus besecured in any of a plurality of convenient positions.

Referring to Figs. 2, 5 and 6, the dividing head 62 preferably includesa base 116 which rotatably supports a substantially cylindrical body 117for rotation about a horizontal axis, which is parallel'to the axis ofthe shaft 41. The cylindrical body 117 is pro- 117 for securing thebody117 in any of a plurality of positions, as, for example, the positionshown in Fig.2. The body 117 is provided with a gear chamber 122, andwith a pair of aligned bores 123 for receiving a sleeve 124 carrying aworm gear 125. The sleeve 124 has a tapered bore 126 at its righthandend in Fig. 6, for receiving a tapered sleeve 127 which is provided withscrew threads 128 adapted to cooperate with complementary threads on thesleeve 129.

The sleeve 129 has a head 130 at its outer end provided with sockets 131for receiving a wrench and an anti-friction bearing comprising a pair ofraces 132, and a plurality of balls 133 may be interposed between thehead 130 and abushing 134 carried by sleeve 129.

The tapered sleeve 127 may beprovided with a split end adjacent the bore135 for receiving the spindle 38, and when the spindle 38 is located inbore 135 and the sleeve 127 is drawn into the taperedbore 126 byrotating the s-eeve head 130, the spindle 38 is firmly gripped bythesleeve 127, forming a substantially firm connection between the spindle38 and the sleeve 124.

The spindle 38 is prefcrablyprovided with a. thrust bearing 136 and witha tapered. reamer supporting portion 39, the axis of.

which is located eccentrically with-respect to the axis of the spindle38 as shown in Fig.4.

The cylindrical body 117 is also provided with bearings for supporting aforwardly extending screw shaft 137,.which is adapted to engage andactuate the screw gear 125 and.

the shaft 137 is provided with a crank138 having a handle 139 providedwith a pin 140 and adapted to be slid axially to withdraw the pin 140from a plate 141.

The plate 141 is fixedly supported upon the cylindrical. body 117 andprovidedwith the minimum amount of holes necessary to secure the handle128 in a plurality of 'difi'er-' ent positions necessary tobe used inadvancing the reamer 10 step by step from the position of one tooth tothe position of the next succeeding tooth. In the present embodiment,the gear ratio is such that one and twothirds turns of the handle .138is sufiicient to advance the spindle 38 and reamer 10 to the positionfor cutting the next tooth, and consequently the plate 141 is providedwith three apertures 142, thereby eliminating the many apertures whichare usually provided in the securing plates of dividing heads andadapting the present machine to the manufacture of the present reamers.

In order to automatically move the table 61, dividing head 62and reamer10 to the proper elevation for the cutting of the successive teeth, thepresent machine is preferably provided with pneumatic devices forantomatically moving the elevation plate 91 T stepv by step into thesuccessive positions necessary to give the reamer 10 the.desiredpredetermined elevation.

Referring to Fig. 10, the platform 89 also preferably supports acylinder 143 which is provided with a cylinder head 144 for slid? ablysupporting one end of a piston rod 145.

The cylinder head 144 is provided. with a packing 146 which may becompressed by means ofv the screw sleeve 147 and the piston rod 145fixedly supports a piston 148, which may be provided with piston rings149.

The opposite end of the rod 145 is slidably supported in a bore 150which is formed in an upwardly extending lug 151 carried by the platform89, and the 'rod145fixedly sup ports a laterally projecting lug 152which is secured in adjusted position by a set screw 153. The lug 152pivotally supports apawl 154, which is urged into engagement with theteeth 92 by aspring 155, the spring being coiled about a pin 156 carriedby a pair of up wardly projecting ears 157 011 the lug 152..

. In order to maintain the pawl 154 in proper position for engagementwith the teeth 92, and to prevent rotation of the piston rod 145, thepiston rod 145 may be provided with a cross-head 159a, which is slidablysupported by a pair of guides 160 carried by platform 89. The guidessupport an adjustable stop 150 for determining the travel of the pawlfor any number of teeth.

7 The ends of the .cylinder 143 are provided with conduits 161, 162leading from the interior of the cylinder 143 to a valve casing 163, andthe. conduits 161, 162 preferably include flexible hose so that thevalve casing 163 may becarried by the table 60, the hose permittingrelative movement between these .parts.

The'valve casing 163 is provided a pair of discharge openings orconduits 164', p

tank (not shown), and the-conduits 161, 162

communicate with the valve casing 16331? points intermediate the supplyconduit and discharge conduits, respectively.

The valve casing 163 is preferably provided with a piston valve .167which is formed with annular grooves .168, 169, which are proportionedin such manner that when the piston 167 is in the position of Fig. 2,.at the bottom of its travel the conduit 166 is in communication throughthe groove 168 with the conduit 161, and when the piston valve 167 is atthe upper limit of its travel, the conduit 166 is in communication withconduit 162 through the groove 169.

which communicates with the other end of the cylinder 143, is incommunication with the atmosphere through the grooves 169 and associateconduit 165. 1

The piston valve 167 thus controls the supply of fluid pressure to thecylinder 143, so that the piston 148 may be reciprocated step by step torotate the plate 91, depending upon the control of the piston valve 167.

The piston valve 167 is provided with a piston rodl70 having a link 171whichconnects to a lever 172, and'the lever 172 is pivotally mounted onthe carriage by means of a bolt 173 carried by a sheet metal bracket174. The left end of the lever 172 carries a roller 175 which is adaptedto be engaged by the upwardly projecting arm 176, and the downwardlyprojecting cam-17 7 carried by the table 61. The cam 177 is adapted toengage roller 175, when the table 61 moves to the right in Fig. 2,moving the lever 17 2 counter-clockwise and drawing the piston valve toits upper position from the position of Fig. 2, while the cam 17 6 isadapted to return the piston 167 to the position of Fig. 2 on the returnmovement of the table 61. r v The operation of theautomatic step by stepmechanism for producing a predetermined elevation of the reamer blank,and consequently a predetermined depth of cut, spacing and angularityfor each tooth, is as follows. j

Referring to Fig. 10, the pneumatic step by step mechanism is shown inthe position which it occupies just after the elevation plate 91 hasbeen moved to a new position, and before the operation of cuttinganother tooth on the reamer.

Referring to Fig. 2, the rear end of the cylinder 143 is incommunication with the source of fluidpressure 166 through the conduit161 and groove 168 of valve 167. 7

When the table 61 is moved to the left by rotating the handles 111 ofthe shaft 110 in a clockwise direction, (Fig. 2), the body of the reamer10 is fed against the milling outter 40, thereby cutting a tooth inthe'reamer 10. The cam 177 is located on the table 61 in such positionrelative to the roller 175 that the cam 17 7 does not engage roller 175until the reamer has passed the milling cutter, at which time the cam177 engages roller 175, moving roller 175 downward, rotating lever 172counterclockwise and moving valve 167 to its upper position. r

This closes exhaustconduit 165 and shuts off the source of fluidpressure to conduit 161, but'places'conduit 161 incommunication withexhaust conduit 164. The cylinder 143 is then incommunication with thesource of fluid pressure 166 through conduit 162, and groove 169, andthe action of the fluid pressure on the forward end of piston 148 movesthe piston from the position of Fig. 10 to the upper end of cylinder14-.

The pawl 154 is thus moved back beyond the next tooth'92 on theelevation plate 91 in position to produce further movement of theelevation plate 91 as soon as fluid pressureis supplied to the rear endof the piston 148. 7

Thehand levers 121 are then rotated in a counter-clockwise direction,and the table 61 is moved tot-he left by screw 112 and rack 113, duringwhich movement the reamer 10 passes the cutter 40 through the cutpreviously formed. As soon as the reamer 10 has cleared the cutter 40 onits return movement, the lower earn 176 then comes into engagement withthe roller 175, moving roller 175 upward, and rotating lever 172clockwise to move the piston 167 from its upper position to the positionof Fig. 2.

Fluid pressure is then admitted to the upper or rear end of cylinder 143through conduit 161, groove 168 and conduit 166, as illustrated in Fig.2, andthe piston 148 is immediately moved to the position of Fig. 10.During this movement, the pawl 154 engages the shoulder 93 upon theadjacent tooth 92 and advances the elevation plate 91 one step, and theroller 82 on the slider 66 which supports the knee 59, carriages 60, 61and reainer 10 is raised or lowered by the elevation plate 91, so'thatthe elevation of the reamer for any tooth may be predetermined by theelevation of the c'amming surfaces 95 on the plate/91, and the elevationplate 91 deter mines the depth of cut at any tooth in the reamer 10. p i

The elevation'plate 91 is preferably provided with a nuinberof cammingsurfaces 95 equal to the number of teeth desired in the reamer 10, andthe cam plate 91 is also provided with an equal number of teeth 92 sothat when one reamer has been made, the cam'plate 91 has progressed stepby step through its entire series of positions until it is again inposition to begin the cutting of a new reamer. -The camming surfaces 95on the plate 91 may take any predetermined form, but they are preferablyprovided with relatively flat surfaces at each of the points of restofthe roller 82, so that the elevation of the roller 82 may be accuratelypredetermined and not affected by slight variations in the rotativeposition of the plate 91.

It will thus be observed that the pneumatic mechanism just described, iscapable of automatically determining the depth of 'nssaeai cut of themilling cutter 40 in the reaxnerlO, and the reamer may be moved backwardthrough the milling cutter to the position for a new out before' theelevation of the reamer is changed. g

It should'be noted that it is desirable that the reamer be movedba-ck toits initial position before the elevation of the'reamer be changed, forthe reason that the next cut may not be as deep as the" cut justcompleted, in which case it would be impossible to baclif the reamerthrough the last out after the new adjustment in elevation.

The operation of the reamer cut-ting machine in the manufacture of thereamers previously described, is as follows.

Referring to Figs. 1 and 11, the initial positionof the table 61 isdetermined. by the depth of the first tooth cut int-he reamer 10,

and the table'61 may be adjusted in its cleva-.

tion' without affecting the operation of the cam plate 91 by merely.rotating the crank 87. hen the Crank 8'? is rotated in a clockisedirection,.the shaft is rotated n a similar direction, rotatingthe shaft(35 in a similar direction by means of the bevel gears 83, 84, and thescrew threads 68 on shaft 65 react against the threads ra se the shaft65 and with it the knee 59, and 'all of its associated mechanism. Acounter-clockwise rotation of the crank 87 will reduce the elevation oftherean'ier sup. porting mechanism by lowering theknee 59. The reamerbody 10 is first located upon the eccentric portion 39 of the spindle38, and if the reamer to be manufactured is a 45 reamer, the cylindricalbody of the divid ing head 62 is rotated until the reamerspindie 38points upward at an angle of 45 to the horizontal, as indicated by thescale 118 with respect to pointer 120. The spindle 38 may be fixed indifferent angular position by means of the thumb screw 121, and the pin140 of crank 139 is located in one of the apertures 142 to preventrotation of the spindle 38.

It is essential that the cutting'of the reamer should begin with theeccentric-part 39 of spindle 38 in the proper position with respect tothe position of the cam plate 91, because the cam plat-e varies theelevation of the reamer, and the elevation of the camming surfaces onthe plate 91 are predetermined by taking into consideration the various-ele-.

vations of the reamer due to the eccentricity in the slider 66, to

by iat marks on each accomplished by advancing the reamer body 10through the milling cutter by means of the hand lever 111, andwithdrawing thereamer past the milling cutter in the manner previ: ouslydescribed.

As soon as the reamer is withdrawn from the cutter, the automaticelevation mechanism is moved one step forward and the elevationplate 91takes the proper position'to raise the reamer or lower it, as the casemay be,.into

the edge 22 in F ig. 7, and this cut may be apredetermined position forthe next cut, the

exact position being determined by the elevation of the next cammingsurface 96 on.

plate 91. The reamer 10 is then rotated one step into the position forthe next cut, and

in forming a fifteen-tooth reamer with the volved in an orbit, theradius of whichorbit the teeth of the reamer extend along lines drawn tothe center 21, and if the reamer body 10 is initially provided with afrusto-conical surface 180, the resulting reamer will be provided withrelatively flat frusto-conical surfaces adjacent each of the cuttingedges 22 to 26.

Since the out which is made in the reamer body is substantiallytriangular in cross-section, a deeper cutspaces the teeth at greaterdistance from each other, and a more shallow cut makes teeth which arecloser together.

An infinite number of different arrangements of the spacing of the teethmaybe made, and the spacing illustrated in Fig. 7 is to be regarded asexemplary of but one form of the reamer. The result of this cuttingoperation is a reamer which has teeth 17 with edges extending alonglines converging in the eccentric axis 21. so that all of the edges onthe teeth are of substantially differ ent angularity.

In order to provide the reamer with a better and more accurate cuttingedge, the reamer is thereafter placed upon an ordinary tapered spindleand rotated upon its true axis with respect to a grinding wheel, whichis adapted to grind a substantially frusto-conical surface. turnsagainstthe teeth and preferably has its axis located slightly below theaxis of the reamer shaft, in order to provide some clearance behind thecutting edge, as described in The grinding wheel preferably detailin myprior application, and as a re.- sult, it is found that the teeth 22-36each have a differentangularity with respect to each other on reamer.

- Since the reamers are ground with a grind- 7 ing device which wouldordinarily produce a frusto-conical surface if other portions of thereamer had not been cut awa the fiat 7 duced by a cut through afrusto-conical surface so that the cutting edges of the teethapproximate lines geometrically known as conic sections. Such lines areslightly curved, the curvature depending upon the plane through whichthe conic section is made, and each one of the teeth represents a conicsection taken at a slightly different angle.

The method of use of the reamers which aremanufactured by the presentmachine,

is described. in detail in my prior application,

and this method of valve seat finishing dif-- fers from the prior artinthe elimination of the step of lapping or grinding the valve and theuse of a plurality of cutting edges disposed at different anglesenablesthe production of a perfectly finished valve seat by a one-step method.Manufacturers of motorcars who have always found itnecessary in theprior art to grind in their valves are.

now enabled to produce a perfect finish upon the valve seats, merely bythe use of a reamer, thereby greatly decreasing the amount of laborinvolvedand the cost of finishing the valve seats. 7

It will thus be observed that I have invented an improved reamermanufacturing machine, which is capable of producing a reamer havinggreatly improved operating characteristics. The present machine ispeculiarly adapted tomanufacture these reamers economically andexpeditiously with a high oegree of quality and but very littlevariation in the dimensions and location of the respective teeth. Itshould be noted that since the present reamer is intended toactually'produce the finished valve seat surface, the teeth should belocated with a high degree of accuracy such as can be attained by theuse of the present machine.

lVhile I have illustrated a preferred em bodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited to the precise details ofconstruction set forth, but desire to avail myself of all changes withinthe scope of the appended claims.

Having thus described my invention, what reamer body including aneccentric shaft,

means for rotating said shaft, step by step, means for feeding saidreamer body against said cutter, and means for changing the elevation ofsaid body between successive cuts,

to varythe depth, and spacing of teeth formed in saidreamer body; I

2. Ina reamer cutting machlne, the combination of a supportmg bEISBWVltha cutter carried thereby, means for supporting a reamer body includingan eccentric shaft, means for rotating said shaft, step by step,means'for feeding said reamer body against said cutter, and means forchanging the elevation of said body between successive cuts, to vary theangularity of teeth formed in said reamer body,

In a reamer cutting machine, the combination of a supporting base with acolumn, a cutter carried by said column, a table movably mounted on saidcolumn, a dividing head carried by said table, an eccentric shaftcarried by said dividing head for rotatably supporting a reamer blank,means for feeding said blank against said cutter, means for rotatingsaid blank step by step, and means for raising said table to apredetermined elevation for each cut to Vary the angularity and depth ofteeth formed on said reamer, said means comprising a rotating platehaving camming surfaces of different elevation.

4. In a reamer cutting machine, the combination of a supporting basewith a column, a cutter. carrier by said column, a table movably mountedon said column, a dividing head carried by said table, an eccentricshaft carried by said dividing head for rotatably supporting a reamerblank, means for feeding said blank against said cutter, means forrotating said blank step by step, means for raising said table to apredetermined elevation for each cut to vary the angularity and depth ofteeth formed on said reamer, said means comprising a rotating platehaving camming surfaces of different elevation, a source of fluidpressure, a cylinder and piston, and a pawl actuated by said piston tomove said plate step by step.

5. In a reamer cutting machine, the combination of a supporting basewith a column, a cutter carried by said column, a table movably mountedon said column, a dividing head carried by said table, an eccentricshaft carried by said dividing head for rotatably supporting a reamerblank, means for feeding said blank against said cutter, means forrotating said blank step by step, means for raising said table to apredetermined elevation for each cut to vary the angularity and depth ofteeth formed on said reamer, said means comprising a rotating platehaving camming surfaces of different elevation, a source of fluidpressure, a cylinder and piston, a pawl actuated by said piston to movesaid plate step by step, and means actuated by a feeding movement ofsaid table to control said piston.

6. in a cutting machine, the combination of a supporting base having acolumn wit-h a table movably supported on said column and having adividing head with a work supporting shaft, said shaft having aneccentrically located work holding arbor, a cutter carried by saidcolumn, means for moving said work holding arbor on said table into thepath of said cutter to out teeth converging toward a point eccentricwith respect to the axis of the work, and means for rotating the workupon an eccentric axis into position for cutting other teeth, and meansfor raising and lowering said table a predetermined amount to regulatethe depth of out between the teeth of the work.

7. In a cutting machine, the combination of a supporting base havingacolumn with a table movably supported on said column and having adividing head with a work supporting shaft, said shaft having aneccentrically located work holding arbor, a cutter carried by saidcolumn, means formoving said work holding arbor on said table into thepath of said cutter to cut teeth converging toward a point eccentricwith respect to the axis of the work, and means for rotating the workupon an eccentric axis into position for cutting other teeth, and meansfor raising and lowering said table a predetermined amount to regulatethe depth of cut between the teeth of the work, comprising a platehaving a plurality of surfaces of predetermined elevation and meanscarried by said table for engaging said surfaces and raising or loweringsaid table on movement of said plate.

8. In a cutting machine, the combination of a supporting base having acolumn with a table mo-vably supported on said column and having adividing head with a work supporting shaft, said shaft having aneccentrically located work holding arbor, a cutter carried by saidcolumn, means for moving said work holding arbor onsaid table into thepath of said cutter to out teeth converging toward a point eccentricwith respect to the axis of the work, means for rotating the work uponan eccentric axis into position for cutting other teeth, and means forraising and lowering said table a predetermined amount to regulate thedepth of out between the teeth of the work, comprising a plate having aplurality of surfaces of predetermined elevation and means carried bysaid table for engaging said surfaces and raising or lowering said tableon movement of said plate, and means for automatically moving

